A retractable dual-inlet isolator inlet

Abstract

The present invention relates to a variable-geometry isolator dual-mode inlet, belonging to the technical field of aircraft; it includes a wedge plate assembly, a variable-geometry isolator, a diffuser section, left and right actuators, and a cowl lip; the lower ends of the wedge plate assembly and the diffuser section are respectively hinged to the fuselage, and the upper ends are respectively hinged to the two ends of the variable-geometry isolator; the distance between the variable-geometry isolator and the cowl lip is the throat height H th , by driving the wedge plate assembly and the diffuser section to rotate around the lower hinge points respectively through the left and right actuators, the length of the variable-geometry isolator and the throat height H th are adjusted so that the aircraft can maintain high aerodynamic performance at different oncoming flow Mach numbers. The variable-geometry isolator dual-mode inlet applying the technical solution of the present invention can adjust the length of the isolator and the height of the throat at different oncoming flow Mach numbers, thereby playing a corresponding stabilizing role on shock waves of different intensities and meeting the throat area requirements of the inlet under a wide speed range, greatly improving the aerodynamic performance of the dual-mode inlet.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft, and particularly relates to a variable-geometry two-dimensional inlet with a variable-length isolator. Background Art

[0002] For a supersonic inlet for large-airspace and wide-speed-range flight, the design difficulty of the inlet lies in the need to balance the performance at low altitude and low speed and the performance at high altitude and high speed simultaneously. At low altitude and low speed, the overall contraction ratio of the inlet usually needs to be designed to be small and the throat to be large; at high altitude and high speed, to fully exert the thrust performance of the engine, it is necessary to improve the compression efficiency of the inlet, and the required throat area is usually small. This contradiction becomes more prominent as the working range of the inlet widens. Conventional fixed-geometry inlets generally adopt a compromise design method, which leads to a decline in the overall performance of the inlet. How to handle the above contradictions is an urgent problem to be solved for the inlet to operate in a wide Mach number range; in addition, the isolator is an indispensable part of a wide-speed-range inlet. Under the action of high back pressure, the airflow continues to decelerate and pressurize inside the isolator, and complex shock wave / boundary layer interference phenomena occur. Therefore, the main function of the isolator is to withstand the change of the downstream back pressure without affecting the flow pattern of the upstream inlet, avoid inlet unstart, and have an aerodynamic and thermal buffering effect. When the incoming flow Mach number is low, the degree of shock wave / boundary layer interference is relatively weak, the length of the shock wave train is short, and the required isolator length is short; as the incoming flow Mach number increases, the shock wave / boundary layer interference intensifies, the length of the shock wave train increases accordingly, and the required isolator length also increases accordingly. When the flow field requirements are met, the increase in the isolator length will increase the complexity of the mechanism and the flow field, increase the wall loss, reduce the total pressure recovery coefficient of the inlet, and ultimately lead to a decline in the overall aerodynamic performance of the inlet. Therefore, how to design a short and efficient isolator while meeting the overall requirements of the engine has become an issue of great concern to relevant researchers.

[0003] In the research on the optimal length of the isolator under real inlet conditions on pages 103 - 108 of the 36th volume, No. 6 of "Computer Simulation" in 2019, the length of different isolators was changed respectively for numerical simulation calculations, and it was obtained that the increase in the isolator length at high Mach numbers would improve the performance of the inlet. However, the adjustability of the isolator was not considered under actual conditions. When an aircraft flies under wide-speed-range conditions, if an adjustable isolator is adopted, the overall performance of the inlet will be greatly improved. Summary of the Invention

[0004] Technical Problems to be Solved:

[0005] To avoid the deficiencies of the prior art, the present invention provides a variable-geometry isolator dual inlet, which can meet the throat area requirements of a wide-speed-range inlet and meet the inlet performance requirements under different shock wave intensities through a variable-geometry isolator, can improve the internal flow field of the wide-speed-range inlet, and increase the total pressure recovery coefficient of the inlet, laying a technical foundation for the engineering application of the wide-speed-range inlet and even the development of advanced aircraft.

[0006] The technical solution of the present invention is: a variable-geometry isolator dual inlet, the head and tail of the inlet are connected to the fuselage; it includes a wedge plate assembly, a variable-geometry isolator, a diffuser section, left and right actuators, and a cowl; the lower ends of the wedge plate assembly and the diffuser section are respectively hinged to the fuselage, and the upper ends are respectively hinged to both ends of the variable-geometry isolator;

[0007] The distance between the variable-geometry isolator and the cowl is the throat height H th , by driving the wedge plate assembly and the diffuser section to rotate around the lower hinge points respectively by the left and right actuators, the length of the variable-geometry isolator and the throat height H th are adjusted so that the aircraft can maintain high aerodynamic performance at different oncoming flow Mach numbers.

[0008] A further technical solution of the present invention is: the wedge plate assembly includes a first-stage wedge plate and a second-stage wedge plate. The lower end of the first-stage wedge plate is hinged to the fuselage, the upper end is fixed to the lower end of the second-stage wedge plate, and the upper end of the second-stage wedge plate is hinged to the variable-geometry isolator;

[0009] The angle between the first-stage wedge plate and the horizontal direction is α, and the angle between the second-stage wedge plate and the horizontal direction is β, where β > α.

[0010] A further technical solution of the present invention is: the left actuator is hinged to the inner side of the first-stage wedge plate through a first connecting rod and a hinge. The left actuator pushes / pulls the first connecting rod in the horizontal direction to make the first-stage wedge plate rotate counterclockwise / clockwise; the right actuator is hinged to the inner side of the diffuser section through a second connecting rod and a hinge. The right actuator pushes / pulls the second connecting rod in the horizontal direction to make the diffuser section rotate clockwise / counterclockwise.

[0011] A further technical solution of the present invention is: when the oncoming flow Mach number 0 < Ma < 5, the angle α of the first-stage wedge plate is 4° - 9°. At the design Mach number, the angle β of the second-stage wedge plate is determined according to the shock wave closure principle; when the oncoming flow Mach number increases, the first-stage wedge plate rotates counterclockwise around the hinge, and the diffuser section rotates clockwise around the hinge; when the oncoming flow Mach number decreases, the first-stage wedge plate rotates clockwise around the hinge, and the diffuser section rotates counterclockwise around the hinge.

[0012] A further technical solution of the present invention is that the telescopic isolation section includes a plug plate and a right thin plate. One end of the plug plate is hinged to the second-stage wedge plate, and a groove is formed on the side wall of the other end. One end of the right thin plate is inserted into the groove of the plug plate, and the other end is hinged to the diffuser section. The plug plate and the right thin plate generate relative displacement driven by the second-stage wedge plate and the diffuser section, thereby changing the total length of the telescopic isolation section.

[0013] A further technical solution of the present invention is that when the incoming flow Mach number Ma < 2.5, the shock wave intensity is weak, and the length of the shock wave train under the high backpressure condition is short. At this time, the length of the telescopic isolation section is L 1 , 2H th < L 1 < 4H th ; As the incoming flow Mach number increases, 2.5 < Ma < 5, the shock wave intensity increases, and the length of the shock wave train under the high backpressure condition increases. At this time, the telescopic isolation section rotates counterclockwise with the first-stage wedge plate and clockwise with the diffuser section, and the total length is extended to L 2 , 4H th < L 2 < 7H th .

[0014] A further technical solution of the present invention is that the depth from the top end of the plug plate to the groove is l, and the grooving depth l < 50L 1 , so the influence on the flow field caused by nesting two plates can be ignored.

[0015] A further technical solution of the present invention is that the left driver drives the first connecting rod to make the first-stage wedge plate rotate around the hinge, and the right driver drives the second connecting rod to make the diffuser section rotate around the hinge; during the rotation process, the telescopic isolation section is always in a horizontal position by controlling the left and right drivers.

[0016] Beneficial effects

[0017] The beneficial effects of the present invention are as follows: The telescopic dual-inlet duct with an isolation section provided by the present invention can meet the performance requirements of the inlet duct at different Mach numbers by adjusting the length of the isolation section, play a corresponding buffering role for different intensities of shock wave / boundary layer interference phenomena, and while adjusting the length of the isolation section, by rotating the wedge plate and the diffuser section, the throat height of the inlet duct changes accordingly to meet the throat height requirements of the wide-speed-range inlet duct at different Mach numbers, and give full play to the thrust performance of the engine. The proposed range of the first-stage inclined plate angle is based on the Oswititsch theory, so that when the inlet duct meets the shock wave sealing, the external resistance is reduced and the total pressure recovery coefficient is increased.

[0018] In the 11th issue, Volume 24, 2009 of the Journal of Aerospace Power, pages 2421 - 2428, a relationship diagram between the isolator length and the maximum back pressure borne by the inlet was obtained. It can be seen from Figure 4 this that as the isolator length increases, the back pressure borne by the inlet increases. Therefore, the retractable isolator structure proposed in this paper can adjust the isolator length at different Mach numbers, and play a corresponding buffering role in the shock wave / boundary layer interference phenomena of different intensities under the action of back pressure. When Ma < 2.5, the shock wave intensity is weak. Shortening the isolator length can buffer the shock wave train while reducing the wall loss. As the Mach number increases, the shock wave intensity increases, and increasing the isolator length can withstand a greater back pressure. The retractable dual - inlet with variable isolator length is based on the traditional non - adjustable dual - inlet, and the forebody wedge and diffuser are designed as adjustable structures, and the isolator is designed as a retractable structure. The difficulty of this invention lies in controlling the left and right drivers to keep the isolator always in a horizontal position. Brief Description of the Drawings

[0019] Figure 1 Figure 1 is the retractable dual - inlet with variable isolator length provided by the present invention.

[0020] Figure 2 Figure 2 is the state when the retractable isolator is at its shortest provided by the present invention.

[0021] Figure 3 Figure 3 is the state after the retractable isolator is extended provided by the present invention.

[0022] Figure 4 Figure 4 is the relationship diagram between the isolator length and the maximum back pressure borne by the inlet.

[0023] Description of the Reference Numerals: 1. First - stage wedge of the dual - inlet; 2. Second - stage wedge of the dual - inlet; 3. Isolator of the dual - inlet; 4. Diffuser of the dual - inlet; 5. Lip of the dual - inlet; 6. Hinge; 7. Link; 8. Left driver; 9. Right driver; 10. Insert plate; 11. Right - hand thin plate. Detailed Embodiment

[0024] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0026] As Figure 1 shown, the present invention provides a retractable dual-inlet with an isolator, including: a first-stage wedge 1, a second-stage wedge 2, a retractable isolator 3, a diffuser 4, a cowl 5, a hinge 6, a connecting rod 7, a left driver 8, and a right driver 9. Among them, the first-stage wedge 1 is hinged to the airframe, the second-stage wedge 2 is fixedly connected to the first-stage wedge 1, the left side of the retractable isolator 3 is hinged to the second-stage wedge 2, the right side is hinged to the diffuser 4, the diffuser 4 is hinged to the airframe, and the two drivers are respectively located below the first-stage wedge 1 and below the diffuser 4.

[0027] For the structure of the retractable dual-inlet with an isolator, the structures of the first-stage wedge, the second-stage wedge, the retractable isolator, and the diffuser are as Figure 1 shown. The first-stage wedge forms an angle α with the horizontal plane. When the incoming flow Mach number 0 < Ma < 5, the angle α of the first-stage wedge is 4° - 9°. At the design-point Mach number, the angle β that the second-stage wedge forms with the horizontal plane can be obtained through the shock-sealing principle. When the incoming flow Mach number increases, the first-stage wedge rotates counterclockwise around the hinge, and the diffuser rotates clockwise around the hinge; when the incoming flow Mach number decreases, the first-stage wedge rotates clockwise around the hinge, and the diffuser rotates counterclockwise around the hinge.

[0028] When the incoming flow Mach number is relatively low (Ma < 2.5), the inlet requires a smaller contraction ratio. At this time, the throat height H th is at its maximum value. Under high backpressure conditions, the shock wave / boundary layer interference at low Mach numbers is relatively weak, the length of the shock wave train is shorter, and the required isolator length is correspondingly shorter. The shortest length of the isolator is L 1 (as Figure 2 shown); as the incoming flow Mach number increases, in order to fully exert the thrust performance of the engine, it is necessary to improve the compression efficiency of the inlet, and the required throat area is usually smaller. At this time, by controlling the left driver 8, the first-stage wedge 1 is rotated counterclockwise around the hinge, and at the same time, by controlling the right driver 9, the diffuser 4 is rotated clockwise around the hinge. During the rotation process, the relative positions of the left plug plate 9 and the right thin plate 10 of the isolator change, causing the length of the isolator to elongate (as Figure 3As shown in the figure; during the process of adjusting the actuating mechanism, the throat height of the inlet decreases, meeting the requirement of a large contraction ratio. Due to the increase in the oncoming flow Mach number, under high backpressure conditions, the shock wave / boundary layer interference is severe and the length of the shock wave train increases. Since the elongation of the isolator makes the shock wave / boundary layer interference stage occur completely within the isolator without affecting the flow pattern of the upstream inlet, it avoids the inlet from unstarting and plays a good buffering role in aerodynamic heat. Through the adjustment of the above adjustable mechanism, the inlet can meet the air intake requirements at different Mach numbers. Under high backpressure conditions, it effectively buffers shock wave trains of different lengths, greatly improving the aerodynamic performance of the inlet and the overall performance of the engine.

[0029] Specifically, the two-dimensional inlet with a telescopic isolator adds an adjustment mechanism on the basis of the traditional non-adjustable two-dimensional inlet, which is convenient for design. By controlling the actuator, it not only meets the requirement of the throat area of the inlet under wide-speed-range flight but also meets the telescopic change of the isolator under different shock wave intensities, greatly improving the total pressure recovery coefficient of the inlet and better meeting the overall performance requirements of the engine.

[0030] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A telescopic dual-inlet with a separable segment, the head and tail of the inlet are connected to the fuselage; Characterized in that: It includes a wedge plate assembly, a telescopic separable segment, a diffuser section, left and right drivers, and a cowl; the lower ends of the wedge plate assembly and the diffuser section are respectively hinged to the fuselage, and the upper ends are respectively hinged to both ends of the telescopic separable segment; The distance between the telescopic isolation section and the lip mask is the throat height H th , the wedge plate assembly and the diffuser section are respectively driven by the left and right drivers to rotate around the lower hinge point, so as to adjust the length of the telescopic isolation section and the throat height H th to ensure that the aircraft can maintain high aerodynamic performance at different oncoming flow Mach numbers; The wedge plate assembly includes a first-stage wedge plate and a second-stage wedge plate. The lower end of the first-stage wedge plate is hinged to the fuselage, the upper end is fixed to the lower end of the second-stage wedge plate, and the upper end of the second-stage wedge plate is hinged to the telescopic isolation section. The angle between the first-stage wedge plate and the horizontal direction is , and the angle between the second-stage wedge plate and the horizontal direction is , ; The telescopic separable segment includes a plug plate and a right thin plate. One end of the plug plate is hinged to the second-stage wedge plate, and a groove is formed on the side wall of the other end; one end of the right thin plate is inserted into the groove of the plug plate, and the other end is hinged to the diffuser section; the plug plate and the right thin plate generate relative displacement under the drive of the second-stage wedge plate and the diffuser section, thereby changing the total length of the telescopic separable segment.

2. The telescopic dual-inlet with a separable segment according to claim 1, Characterized in that: The left driver is hinged to the inner side of the first-stage wedge plate through a first connecting rod and a hinge. The left driver pushes / pulls the first connecting rod in the horizontal direction, so that the first-stage wedge plate rotates counterclockwise / clockwise; the right driver is hinged to the inner side of the diffuser section through a second connecting rod and a hinge. The right driver pushes / pulls the second connecting rod in the horizontal direction, so that the diffuser section rotates clockwise / counterclockwise.

3. The telescopic dual-inlet with a separable segment according to claim 2, Characterized in that: When the incoming flow Mach number is 0 < Ma < 5, the angle of the first-stage wedge plate is 4° - 9°. At the design Mach number, the angle of the second-stage wedge plate is determined according to the shock closure principle ; when the incoming flow Mach number increases, the first-stage wedge plate rotates counterclockwise around the hinge, and the diffuser section rotates clockwise around the hinge; when the incoming flow Mach number decreases, the first-stage wedge plate rotates clockwise around the hinge, and the diffuser section rotates counterclockwise around the hinge.

4. The telescopic dual-inlet with a separable segment according to claim 1, Characterized in that: When the incoming flow Mach number Ma <2.5, the shock wave intensity is weak, and the length of the shock wave train under the high back pressure condition is short. At this time, the length of the telescopic isolator is L 1 , 2 H th < L 1 <4 H th ; As the incoming flow Mach number increases, 2.5 < Ma <5, the shock wave intensity increases, and the length of the shock wave train under the high back pressure condition increases. At this time, the telescopic isolator rotates counterclockwise with the first-stage wedge plate and clockwise with the diffuser section, and the total length is extended to L 2 , 4 H th < L 2 <7 H th .

5. The telescopic dual-inlet with a separable segment according to claim 1, Characterized in that: The depth from the top of the inserted plate to the slot is l , and the slot depth l <50 L 1 , so the influence on the flow field caused by nesting two plates can be ignored.

6. The telescopic dual-inlet with a separable segment according to claim 1, Characterized in that: The left driver drives the first connecting rod to make the first-stage wedge plate rotate around the hinge, and the right driver drives the second connecting rod to make the diffuser section rotate around the hinge; during the rotation process, by controlling the left and right drivers, the telescopic separable segment is always in a horizontal position.

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